Difteria en Venezuela: análisis de las manifestaciones clínicas y evolución de una serie de casos

Objetivo: Analizar las manifestaciones clínicas y evolución de los casos sospechosos o confirmados de Difteria en Venezuela. Materiales y Métodos: Se realizó un estudio prospectivo, observacional, descriptivo, longitudinal y multicentrico en los estados Anzoátegui, Bolívar, Carabobo, Distrito Capital, Lara, Mérida, Miranda y Zulia, se siguieron 48 pacientes sospechosos o confirmados para difteria y se describieron sus características clínicas. Resultados: 54,2 % fueron de sexo femenino, 2 de ellas embarazadas, 1 de ellas falleció. La localización más frecuente de lesiones fue la faríngea, sin embargo se observaron otras como la tonsilar, laringotraqueal, nasal y cutánea. Todos los pacientes recibieron antibióticos pero solo 32 toxina antidiftérica. Solo 11 pacientes tenían esquema vacunal completo y 18 presentaron complicaciones. El 18,8 % de la muestra falleció y el resto egresó sin secuelas. Conclusiones: El brote de difteria en Venezuela sigue activo, las cifras de pacientes afectados invitan a implementar estrategias de control a través de la inmunización de susceptibles, erradicación de portadores asintomáticos, diagnóstico temprano, reporte obligatorio, atención y manejo adecuado de los infectados.

Objective: To analize the clinical manifestations and evolution of suspected or confirmed cases of Diphtheria in Venezuela. Methods: A prospective, observational, descriptive, longitudinal and multicentric study was conducted in the Venezuelan's states of Anzoategui, Bolivar, Carabobo, Capital District, Lara, Merida, Miranda and Zulia. The time 1 of the investigation was at the hospital admission and the final time was at discharge. During the hospitalization, the follow-up was performed. Results: 48 patients were followed and all of them had suspected or confirmed Diphtheria. 45,5 % were men and 54.2 % were female, 2 of them were pregnant, and 1 of them died. The most frequent location of lesions was the pharyngeal, however other location were observed such as tonsillar, laryngotracheal, nasal and cutaneous. All patients received antibiotics but only 32 diphtheria antitoxin. Only 11 patients had a complete vaccination scheme and 18 (36 %) had complications. 18.8 % of the sample died and the rest withdrew without sequelae. Conclusions: The diphtheria outbreak in Venezuela is still active, the number of affected patients invite to implement strategies of control through the immunization of susceptibles, eradication of asymptomatic carriers, early diagnosis, mandatory reporting, care and adequate management of the infected.

Human leukocyte antigen class I and MICA haplotypes in a multicase family with Cladophialophora carrionii chromoblastomycosis.

Previous studies carried out in an endemic semiarid region northwest of Venezuela at Falcon State have shown a prevalence of 15.4/1000 of chromoblastomycosis following traumatisms with xenophile vegetation infected with Cladophialophora carrionii. We performed high-resolution DNA typing of human leukocyte antigen (HLA)-A, -B and -C and major histocompatibility complex class I chain related gene A (MICA) alleles and segregation analysis in 49 members of one extended family with 12 affected individuals, who have lived for approximately 70 years in this endemic zone. None of the alleles, haplotypes or genotypes is shared by all the patients. No deviation from the expected HLA haplotype distribution or association of chromoblastomycosis with HLA-A, -B and -C haplotypes was observed. Further, a haplotype-sharing transmission/disequilibria testing of 11 nuclear families did not give enough evidence to claim linkage (P = 0.398), suggesting that genes located in the short arm of chromosome 6 may not be relevant in the immune response toward infection with C. carrionii in this Venezuelan endemic zone. Deleted MICA alleles on HLA-B*4802 haplotypes were present among several members of the extended family, but only two of them were affected.

Inhibition of p38alpha MAPK enhances proteasome inhibitor-induced apoptosis of myeloma cells by modulating Hsp27, Bcl-X(L), Mcl-1 and p53 levels in vitro and inhibits tumor growth in vivo.

Inhibition of p38 kinase blocks the production of tumor-promoting factors in the multiple myeloma (MM) bone marrow microenvironment. Proteasome inhibitors MG132 and bortezomib have been shown to have direct cytotoxic effects on MM cells. We show that a selective inhibitor of p38alpha, SCIO-469, enhances the ability of MG132 and bortezomib to induce the apoptosis of MM cells. Previously, we showed that p38 inhibition with SCIO-469 enhances MM cytotoxicity of bortezomib by inhibiting the transient expression and phosphorylation of Hsp27, a downstream target of p38. Here we show that continued treatment of MM cells with bortezomib leads to a SCIO-469-enhanced downregulation of Hsp27 and to increased MM apoptosis. Furthermore, we show that p38 inhibition enhances the bortezomib-induced MM apoptosis by upregulation of p53 and downregulation of Bcl-X(L) and Mcl-1. In a mouse xenograft plasmacytoma model of MM, we found that inhibiting p38 augments the effects of bortezomib in decreasing MM tumor growth in vivo. Thus, in addition to its role in suppressing an activated MM microenvironment, co-treatment with a p38 inhibitor, such as SCIO-469, may enhance the cytotoxicity of bortezomib by modulating pro-apoptotic and anti-apoptotic factors in MM cells, suggesting great potential for co-therapy.

Cutting edge: bacterial flagellin activates basolaterally expressed TLR5 to induce epithelial proinflammatory gene expression.

Flagellin, the structural component of bacterial flagella, is secreted by pathogenic and commensal bacteria. Flagellin activates proinflammatory gene expression in intestinal epithelia. However, only flagellin that contacts basolateral epithelial surfaces is proinflammatory; apical flagellin has no effect. Pathogenic Salmonella, but not commensal Escherichia coli, translocate flagellin across epithelia, thus activating epithelial proinflammatory gene expression. Investigating how epithelia detect flagellin revealed that cell surface expression of Toll-like receptor 5 (TLR5) conferred NF-kappaB gene expression in response to flagellin. The response depended on both extracellular leucine-rich repeats and intracellular Toll/IL-1R homology region of TLR5 as well as the adaptor protein MyD88. Furthermore, immunolocalization and cell surface-selective biotinylation revealed that TLR5 is expressed exclusively on the basolateral surface of intestinal epithelia, thus providing a molecular basis for the polarity of this innate immune response. Thus, detection of flagellin by basolateral TLR5 mediates epithelial-driven inflammatory responses to Salmonella.

RIP2 is a Raf1-activated mitogen-activated protein kinase kinase.

RIP2 is a serine-threonine kinase associated with the tumor necrosis factor (TNF) receptor complex and is implicated in the activation of NF-kappaB and cell death in mammalian cells. However, the function of its kinase domain is still enigmatic as it is not required in engaging these responses. Here we show that RIP2 activates the extracellular signal-regulated kinase (ERK) pathway and that the kinase activity of RIP2 appears to be important in this process. RIP2 activates AP-1 and serum response element regulated expression by inducing the activation of the Elk1 transcription factor. RIP2 directly phosphorylates and activates ERK2 in vivo and in vitro. RIP2 in turn is activated through its interaction with Ras-activated Raf1. Kinase-defective point and deletion variants of RIP2 also significantly blocked the activation of ERK2 by TNFalpha but not epidermal growth factor. These results describe a novel pathway of ERK activation and the first catalytic function ascribed to any of the RIP-like kinases associated with the TNF receptor superfamily.

RIP3, a novel apoptosis-inducing kinase.

RIP3 is a novel gene product containing a N-terminal kinase domain that shares extensive homology with the corresponding domain in RIP (receptor-interacting protein) and RIP2. Unlike RIP, which has a C-terminal death domain, and RIP2, which has a C-terminal caspase activation and recruitment domain, RIP3 has a unique C terminus. RIP3 binds RIP through its unique C-terminal segment and by virtue of this interaction is recruited to the tumor necrosis factor (TNF) receptor-1 signaling complex. Previous studies have shown that RIP mediates TNF-induced activation of the anti-apoptotic NF-kappaB pathway. RIP3, however, attenuates both RIP and TNF receptor-1-induced NF-kappaB activation. Overexpression studies revealed RIP3 to be a potent inducer of apoptosis, capable of selectively binding to large prodomain initiator caspases.

RAD9 and DNA polymerase epsilon form parallel sensory branches for transducing the DNA damage checkpoint signal in Saccharomyces cerevisiae.

In response to DNA damage and replication blocks, yeast cells arrest at distinct points in the cell cycle and induce the transcription of genes whose products facilitate DNA repair. Examination of the inducibility of RNR3 in response to UV damage has revealed that the various checkpoint genes can be arranged in a pathway consistent with their requirement to arrest cells at different stages of the cell cycle. While RAD9, RAD24, and MEC3 are required to activate the DNA damage checkpoint when cells are in G1 or G2, POL2 is required to sense UV damage and replication blocks when cells are in S phase. The phosphorylation of the essential central transducer, Rad53p, is dependent on POL2 and RAD9 in response to UV damage, indicating that RAD53 functions downstream of both these genes. Mutants defective for both pathways are severely deficient in Rad53p phosphorylation and RNR3 induction and are significantly more sensitive to DNA damage and replication blocks than single mutants alone. These results show that POL2 and RAD9 function in parallel branches for sensing and transducing the UV DNA damage signal. Each of these pathways subsequently activates the central transducers Mec1p/Esr1p/Sad3p and Rad53p/Mec2p/Sad1p, which are required for both cell-cycle arrest and transcriptional responses.

DNA polymerase epsilon links the DNA replication machinery to the S phase checkpoint.

Inhibition of DNA synthesis induces transcription of DNA damage-inducible genes and prevents mitotic entry through the action of the S phase checkpoint. We have isolated a mutant, dun2, defective for both of these responses. DUN2 is identical to POL2, encoding DNA polymerase epsilon (pol epsilon). Unlike sad1 mutants defective for multiple cell cycle checkpoints, pol2 mutants are defective only for the S phase checkpoint and the activation of DUN1 kinase necessary for the transcriptional response to damage. Interallelic complementation and mutation analysis indicate that pol epsilon contains two separable essential domains, an N-terminal polymerase domain and a C-terminal checkpoint domain unique to epsilon polymerases. We propose that DNA pol epsilon acts as a sensor of DNA replication that coordinates the transcriptional and cell cycle responses to replication blocks.

DNA damage and cell cycle regulation of ribonucleotide reductase.

Ribonucleotide reductase (RNR) catalyzes the rate limiting step in the production of deoxyribonucleotides needed for DNA synthesis. In addition to the well documented allosteric regulation, the synthesis of the enzyme is also tightly regulated at the level of transcription. mRNAs for both subunits are cell cycle regulated and inducible by DNA damage in all organisms examined, including E. coli, S. cerevisiae and H. sapiens. This DNA damage regulation is thought to provide a metabolic state that facilitates DNA replicational repair processes. S. cerevisiae also encodes a second large subunit gene, RNR3, that is expressed only in the presence of DNA damage. Genetic analysis of the DNA damage response in S. cerevisiae has shown that RNR expression is under both positive and negative control. Among mutants constitutive for RNR expression are the general transcriptional repression genes, SSN6 and TUP1. Mutations in POL1 and POL3 also activate RNR expression, indicating that the DNA damage sensory network may respond directly to blocks in DNA synthesis. A protein kinase, Dun1, has been identified that controls inducibility of RNR1, RNR2 and RNR3 in response to DNA damage and replication blocks. This result suggests that the RNR genes in S. cerevisiae form a regulon that is coordinately regulated by protein phosphorylation in response to DNA damage.